An X-ray tube is, generally, used for a system which sees through the inside of human bodies or goods, such as a medical diagnosis system and an industrial diagnosis system. The X-ray tube has a cathode, an anode target and a vacuum envelope which houses the cathode and the anode target therein. By applying a high voltage between the cathode and the anode target, electrons emitted from the cathode side impinge on the anode target and thereby X-rays emanate from the anode target.
When the electrons emitted from the cathode impinge on the anode target, the anode target is heated and becomes high temperature. In addition, the cathode also becomes high temperature because a filament is heated so that the cathode emits thermal electrons. When a high-voltage plug is connected to the cathode and a high voltage is applied between the cathode and the anode target, heat of the cathode transfers the high-voltage plug and an insulating part of the high-voltage plug deforms. Accordingly, there is a possibility that a dielectric breakdown may arise.
JP, PH08-96889A discloses a high-voltage connector of a form provided in order to cover onto and be inserted into a high-voltage connection portion provided in a vacuum casing of an X-ray tube. JP, PH08-96889A also discloses that the high-voltage connector has a cooling channel for coolant.
JP, P2008-293868A discloses a structure having a housing and a high-thermal-conductivity insulating member. The housing houses a high-voltage cable end and a high-voltage terminal, and insulates and holds them with an insulating sealing member filled up inside thereof. The high-thermal-conductivity insulating member is fixed to an inner wall of the housing, contacts to the high-voltage terminal thermally and has a larger thermal conductivity than that of the insulating sealing member. JP, P2008-293868A also discloses that the high-thermal-conductive insulating member releases heat, which is transferred from the anode via the high voltage terminal, to the housing.
JP, P2007-42434A discloses that a support member is held by a connection portion which is connected to a tube container at one end side of the support member projected from an envelope and between the envelope and a power feeding part, and discloses that heat accumulated in an insulating material is released via the support member in contact with the insulating material.
JP, P2007-42434A further discloses that heat of the support member transfers to the insulating material and the tube container, and becomes easy to be released from the tube container, the heat release characteristic of the support member improves, and, thereby temperature of the power feeding part can be lowered.
JP, P2001-504988A discloses an X-ray tube of which a high-voltage insulating member is surrounded by potting material and an external surface of the potting material is cooled.